The Nuclear Regulatory Commission has cited the Tennessee Valley Authority for two violations over a 2014 incident at its Browns Ferry Nuclear Power Plant that caused reactor equipment to unexpectedly shut down.
In a letter sent Friday to TVA, the NRC wrote that a former operations shift manager at the Limestone County plant had exercised “poor judgment” when he failed to follow procedure and “deliberately provided information to TVA that was incomplete and inaccurate.”
According to the NRC, the shift manager violated procedure when he manipulated a control board switch normally reserved for an on-duty reactor operator.
In doing so, he inadvertently cut power to the board, which resulted in the temporary loss of a reactor water cleanup pump, a spent fuel cooling pump and other equipment.
The loss of reactor pumps would have caused the reactor to eventually begin overheating, according to David Lochbaum, director of nuclear safety for the Union of Concerned Scientists, but the immediate risk to the facility and the public was minimal.
“It wasn’t overly urgent, but it was something they would have handled before they went to lunch,” he said.
In a statement, TVA said no changes in reactor operation or conditions were noted and that there was no danger to the public or employees. The incident did not damage any equipment, TVA said.
While the problem was corrected quickly, the shift manager did not inform TVA officials of his involvement in the Dec. 21, 2014, incident until the next day.
The NRC finished its investigation Jan. 8 and cited TVA for two violations Friday — one for the shift manger manipulating the control board and one for the shift manager failing to immediately notify TVA management of his involvement.
Both violations were classified at the NRC’s lowest severity level, which does not require TVA to pay any fines.
“The NRC has concluded the poor judgment of the (shift manager) is not reflective of a larger concern with procedural noncompliance involving operations staff,” Joel Munday, NRC regional director of reactor safety, wrote in a letter to TVA Vice President of Nuclear Licensing Joseph Shea.
The identity of the shift manager was not known, but TVA said in a statement that he no longer works at the Browns Ferry plant, does not hold a nuclear clearance with TVA or a nuclear operator license.
“TVA takes the safety of our nuclear facilities very seriously and holds our licensed nuclear operators to the highest standards,” TVA spokesman Jim Hopson said.
The violations come as NRC continues reviewing TVA’s request to increase licensed thermal power levels at the plant by about 14 percent above current limits, which would result in an increase of about 500 megawatts between the plant’s three reactors.
The group Bellefonte Efficiency & Sustainability Team and its affiliated group, Mothers Against Tennessee River Radiation, have filed an intervention calling on the NRC to reject the request and seek a public hearing on the issue.
Mark Leyse, a nuclear safety consultant for BEST, argued TVA’s computer modeling is flawed and that the increase will make the plant more likely to suffer a meltdown during a loss of coolant accident.
NRC spokesman Roger Hannah said TVA already had addressed violations at the plant and that they should have no bearing on NRC’s review of the up-rate request.